For her boyfriend’s 26th birthday on Thursday, Molly Brown booked a night in a luxury tent on a private island on Annabessacook Lake in Monmouth.

“We were sitting on the couch and I was secretly looking at Airbnb listings,” said Brown, 29, talking on the phone from Big Island. “I booked it at 10:30 and then we were on the pontoon boat at 3 p.m. to stay here.”

In less than 24 hours, the couple — she’s from Portland, he’s from Massachusetts — swam in the lake, jumped off a rope swing, napped in a hammock, cooked dessert over a campfire and hiked to find the best spots to look at stars.

“We’re sitting in the tent right now and just marveling at how wonderful it is,” she said.

Owners Kent Ackley and Joanne Weiss have had a banner summer listing both the luxury tent and a log cabin on a nearby private, quarter-acre island for rent online.

It’s the same story across Maine.

More than 141,000 people stayed in Airbnb rentals between Memorial Day and Labor Day this year in Maine, up 60 percent from last summer, according to company figures released this week.

That growth comes after Airbnb’s business doubled in Maine from 2015 to 2016.

Guests spent more than $23 million on their stays this summer. Kelly O’Neil, the owner of Rangeley Vacation Rentals, listed 20 properties on Airbnb in June for the first time.

Business was up by about 25 percent.

“That’s where we got probably half of our renters from this summer, so it was definitely a good call,” she said. “(Guests) are kind of all over the place. I had one this summer from Paris, France, and I had a bunch of last-minute weekenders from the Maine area.”

Airbnb is the largest vacation rental site in an increasingly growing industry. The Vacation Rental Professionals of Maine trade group estimates 21,000 people are now offering Maine rooms, homes and camps on the Web, a number that’s doubled in the past 10 years.

Those listing on sites such as Airbnb, VBRO and HomeAway say worldwide exposure and the ease of booking online are partly behind the upswing.

Greg Dugal, director of government affairs for the Maine Innkeepers Association, said some of the original tension between establishment and newcomers has fallen away as the vacation rental industry’s grown.

“You have to remember, you can go back to the rusticators renting out their rooms (to people summering on the coast in the 1800s) — the short-term rental market has a long history in the state of Maine. It’s not going anywhere,” Dugal said. “There’s only 1,400 lodging licenses (in Maine) and there are tens of thousands of these short-term rentals, so I think it’s a matter of like anything in life, you need to learn to peacefully co-exist.”

Part of keeping that peace: Making sure everyone pays their taxes. And that could wind up back in front of the Legislature this winter.

ENTER THE GOAT

There are hundreds of listings within a half-hour of Lewiston: A room in a country house past Bates College for $18 a night. An apartment off a Pownal farmhouse for $37. A Sabattus Lake house with a boat for cruising or fishing for $95.

Karl Schatz helps reel in guests with two words: goat hike.

Schatz and his wife, Margaret Hathaway, own Ten Apple Farm in Gray. They’ve had the farm with Alpine dairy goats for 12 years, and for the past two years have rented out a small house on an adjoining property that Hathaway’s dad had lived in during retirement.

A path runs between the houses, and guests are invited to learn to milk goats or join them on a goat hike on their 18 acres. (It’s as Maine as it sounds: a gentle hike through the woods with loose, frolicking goats.)

“I was telling him, ‘I don’t know about milking. I can’t promise I’ll have the courage to do it,'” said Rachel Nash of Brooklyn, who stayed there earlier this month with her husband.

Turned out milking was easy, but, “I think the goat was a little bit annoyed at me,” she said.

Nash said they were looking for a vacation spot close to Portland, but outside the city, for day trips and checking out cider houses. The unique experience of the farm was a draw.

Sally Cote, of Greenville, South Carolina, said it was her first time using Airbnb when she stayed at Schatz’s this summer. She needed a place close to her in-laws, where family and friends — along with the bride and groom — could stay for their nearby wedding.

“It just made a lot more sense to rent one house than several broken-up hotel rooms or cottages,” Cote said. “We didn’t find out about all the cool other stuff about them that just made our stay so thoroughly enjoyable until after we booked, to be honest.”

Gretchen Anderson started listing her stately Bethel house — six bedrooms, on a golf course, with an elevator — on VRBO in 2012 after her husband was transferred to California for work and the property didn’t sell.

Named Bingham House, it rents for $550 a night. Most guests are from out of state.

“A lot of it is discovering the area after they found the house, rather than coming for the area first,” Anderson said.

Rental fees have funded upkeep such as repaving the driveway and replacing windows, and it allows the Andersons to come back to Bethel several times a year.

When guests book a stay, Anderson provides ideas for day trips, lists of restaurants, names of personal chefs and contacts for services that will come to the house to give a massage. She said she likes that it’s spreading money around the community.

TAXING QUESTIONS

Overnight stays in Maine are big business: The state recorded $948 million in lodging sales last year, according to Maine Revenue Services.

This year, through July, sales have hit $515 million, up almost 10 percent year-to-date over last year.

If business remains up 5 percent a month for the rest of the year, it could crack $1 billion, Maine Office of Tourism Director Steve Lyons said.

His office started collecting limited data on Airbnb last year. Their research has shown 16 percent of people using the internet to plan a vacation in Maine said they used that service.

One concern outside the industry: that all of those 21,000 room, home and camp hosts aren’t reporting sales and turning in the state’s 9 percent lodging tax.

By Maine law, someone renting a room or home for more than 15 days a year, or having a property manager rent it out for them for any length of time, must collect the lodging tax.

After entering an agreement with the state, Airbnb started automatically collecting taxes at booking in April. Between April 1 and Aug. 31, it’s so far paid the state $2.3 million, according to a spokesman.

Last spring, Gov. Paul LePage proposed creating a rental registry with Maine Revenue Services that would make it easier to check up on tax collections. Diane Johanson of the Maine Tourism Association said it came out of the Legislature’s Taxation Committee with unanimous support but wasn’t in LePage’s final, passed budget.

State Rep. Gary Hilliard, R-Belgrade, has asked the Legislature to consider it again as an emergency bill during the short winter session.

It’s a level-playing-field issue, Johanson said.

Justin Ford, vice president of Vacation Rental Professionals of Maine, which supports paying the tax, said Maine stands out in the vacation rental market on the East Coast for being in a unique position. Unlike Florida, North Carolina and Cape Cod, people here aren’t generally buying a property with an eye toward renting it out to turn a profit, he said.

More often, homeowners using the 196 websites that offer rentals already have a property and they’re doing it to help pay for pricey waterfront taxes or upkeep, he said.

“Or, they’re seasonal homes that have been in the family for four to five generations,” Ford said. “Grandpa Warbucks used to work for Standard Oil and bought the family estate, money’s run dry and now you’re dealing with the fourth generation cousins who are doing $30,000, $40,000-a-year annual jobs, so the only way they can keep their home is by renting it out.”

Maine also stands out in how few large properties it has in the mix compared to other states: Of all those thousands, fewer than 200 sleep eight or more people in a traditional bedroom sense, according to Ford.

“Obviously, there’s hunting camps where there’s 20 bunk beds and you can turn them into a refugee center, but when it comes to a quality home, when you go down to North Carolina, or Virginia Beach, there’s tons of investment homes that are six and eight bedrooms,” he said. “In Maine, people who can afford to own a home that nice can also afford not to rent it out, so there’s not a lot of larger homes.”

The average house for rent here has 2½ bedrooms, he said.

Then, there are the the luxury tents.

Ackley and Weiss have rented the private log cabin on Little Cabin Island on Airbnb for three years. They added what they call the “Maine Island Luxury Tent” this past June. Neither has electricity or running water, and both have been busy all summer.

“Little Cabin was booked most of July and August,” Weiss said. “I think there might have been a total of seven or eight nights that didn’t get booked for the entire two months.”

“I hiked 300 miles of the Application Trail and never saw a toilet like that,” Jacobs said.

kskelton@sunjournal.com